Fuel system



25 1945. J. o. HELVEN r-:T AL 2,385,513

FUEL SYSTEM Filed Oct. 15, 1942 2/ Wei/ze' 6175 @s a7 lai lproviding a greater circulating pump Patented Sept. 25, 1945i UNITED j STATES' PATENT orifice FUEEM i Everett L. Baugh, Dayton, eneral Motors Corporation, Detroit, Mich., a corporation of Delaware Application October 15, 1942, Serial No. 462,172

(Cl. s-36.3)

James 0. Helvern and Ohio, assignors to G 6 Claims.

The engine fuelsystem .which is the subject matter of this application may be described as an improvement over that of a prior filed application Serial No. 456,797 now Patent N0. 2,367,055. Like the system earlier designed it employs a conduit for the flow of fuel which conduit includes as parts thereof a circulating pump, preferably driven by the engine, and a venturi serving to draw into the fuel column from a reservoir a quantity of fuel commensurate with the quantity withdrawn for the operation of the engine.

The improvement which constitutes the subject matter relates to the provision for priming the system.

It has for its object a positive priming action by which fuel is pumped directly from the tank to the carburetor before air is fully exhausted from the system.

Secondly, if the condiut be considered as comprising two pipes between the pump and reservoir only one of these pipes need be filled with fuel before the carburetor is supplied. In consequence the engine is quickly started and thus capacity for priming.

The novel priming valve makes unnecessary the check valve in the pipe leading to the carburetor of the former design. This is desirable in that the movable member of the novel valve is held closed during the early ,priming stage by a relatively heavy spring thus providing a more nearly positive seal. After this initial priming the memberl is moved to awide open position by fluid pressure, thus reducing wire drawing and loss ofc-pressure. `TIt also avoids the need of the air dome which was used in the earlier design becauseof the' check valve. Also throttlingof the high pressure to the venturi caused by the priming-valve ofthe earlier design is largely avoided, the throttling being reduced to the wide gpen position of the new valve.

` The location of thepriming valve adjacent or as "'a part of the rpump makes it accessible for inspection and repair.

the lower end of pipe struction of the cage Other advantages will be apparent from the l description which follows.

In the drawing:

Fig. 1 is a view in side elevation.

Fig. 2 is a vertical transverse section through the circulating pump.

Fig. 3 is a transverse section through the part of the system adjacent the bottom of the fuel tank.

Figs. 4, 5 and 6 are vertical sections through Referring to the priming valve showing its movable member in three positions.

the drawing the engine is marked the carburetor I3 and the fuel tank l5. Numeral |1 is applied to the circulating pump. It delivers fuel under pressure through pipe I9 to a valve identified as lwhole by numeral 2|. In the normal operation ofthe engine fuel-leaves the valve by way of pipe 23 which extends through the top of the tank and to and into a cage 25 near the bottom wall. The fuel returns to the circulating pump through a pipe 21, this pipe including a venturi flared end 3| of which is received in the cage as shown. The cage is surrounded by a screen 33 through which fuel may pass from the tank to enter the narrow region of thev venturi. From 23 the fuel passes through a screen 35 .and up through a nozzle 31 immediately below the venturi. Insofar as the conis concerned it will be seen that this improved design differs from the earlier design mainly by the omissonnof the priming device in the cage including a movable member and spring. There are thus no movable parts in the relatively inaccessible part of the system. f

The circulating pump shown is like that of the earlier design. It is operated by the engine cam`39 and includes the levers 4|, 43 connected diaphragms 45 and 41 and springs 48, 5|, 53 all housed within a casing 55. From the pump adjacent its inlet from pipe 21 is a pipe 51 for supplying the carburetor. Instead of being directly connected to the carburetor it is con'- nected to valve 2| and from the valve a pipe 59 is connected to the. carburetor.

More for the purpose of clear disclosure than to show the production form the valve `is shown separate from the-pump. In production the valve may and probably will be made a part of the pump.

The valve has a longitudinal passage within which reciprocates a valve member 6| normally biased to the position shown in Fig. 4 by a spring 53 within an enlarged part of the passage and in abutment against a threaded plug 65. A disc 61 on the member 6| engages a seat 69 on the valve body around the member 6|. A passage 1| in the valve body communicates with a `radial pass age 13 which opens into pipe 59. A radial passage 15 connects the main passage with passage 1|. The movable valve member is reduced centrally to form an annular channel 11 and it has 29, the lower u al' l at one end an axial passage 19 communicating with radial passages 8|. f

The operation of the system is this. Fig. 4 shows the position of` the parts of the valve when the engine is at rest. Whenthe engine starts under the influence of the starting motor the pump diaphragms reciprocate. Fuel is drawn up through pipe 21 and the air and `fuel is exhausted through pipe |9. As soon as pipe 21 is filled with fuel, the carburetor is supplied through pipe 59, since the position of valve member 6| provides a fluid path through passages 19, 8|, 1|, 13. iIn this position the outlet to pipe 23 is closed. As the engine begins to rotate on its own power the pump action becomes more effective and the pressure acting on member 6| moves it against spring 63 to the position shown by Fig. 5 where the outlet to the carburetor is partially open. Also pipe 23 is partially opened to permit fuel to fill the pipe 23. When the pipe 23 is iilledthe pressure is built .up sufciently'to move member 6| to the position shown in Fig. 6. In this position the opening from passage 19 to 1| is closed and there is a free ow through the valve between pipes I9 and 23. At the same time the annular groove 11 moves to a position such that pipe 51 from the pump may discharge fuel through the valve to pipe 59 and supply the carburetor. Under these circumstances there is a continuous flow of fuel through the valve. The engine requirements are supplied through pipes 51 and 59 and the necessary replenishment is taken in from they tank through the venturi. 'I'he improved valve thus facilitates the starting since only a part of the conduit system need be primed before the carburetor is supplied. A check valve in the pipe leading from the pump is no longer needed.

The location of the priming valve adjacent to or as a part of the pump makes it of easy access for inspection and repair.

'I'here is no 'appreciable throttling of the pipe to the venturi since the valve member completely We claim:

l. A fuel system to supply an engine with` fuel from a tank, said system having a main conduit and a branch conduit, a circulating pump with high pressure and low pressure sides and located within and constituting a part of said main conduit, a pipealso constituting a part of said main conduit connecting said tank to the low pressure side of the pump, mechanism associated with said pipe and operable to add fuel to said pipe from said tank, a priming valve having a passage therein, said -passage having inlet and outlet openings, a second pipe connecting said inlet opening with the high pressure side of the pump, a third pipe connecting the outlet openinglwith said mechanism whereby said second and third pipes with said passage constitute a part of said first conduit, a member movable in said passage to a first position where it cuts off flow between said inlet and outlet openings, said priming valve having a third opening, said movable member constructed to provide communication between said inlet opening and third opening when in said rst position, said branch conduit being connected to said third opening for-supplying said engine,

said priming valve having a fourth opening, coni communicate.

2. 'Ihe invention defined by claim 1, together with yielding means to bias said valve member to its rst described position.

3. The invention defined by claim l, saidmechanism being agventuri. I

4. In a fuel supply system for an` engine, a tank, a pump, a priming valve having an elongated passage, a main conduit, said main conduit having a first part extending from adjacent the bottom. of said tank to said pump inlet, a second part connecting said pump outlet to said elongated .passage in said valve, a third part extending from said valve passage and into said tank, a venturi in said tank connecting the adjacent ends of said first and third parts of the a second conduit connecting the a third conduit communicating with said valve4 passage and adapted to supply fuel to the engine, a movable valve member in said valve passage and a spring to bias said valve member to a position wherein it prevents said second and third a flow of iiuid between and third conduits and also having a recess to connect said last named openings when moved by fluid pressure against the resistance of said spring whereby fluid may fiow from the second conduit to the third conduit.

6. A fuel system to supply an engine from a tank of fuel, said system including a main conduit having first, second and third parts, a pump having an inlet and an outlet, said first'part contherewith, said second part of'the main conduit connecting the pump outlet with the first valve passage opening, said third part connecting the second valve passage opening to the tank, Venturi means connected to said rst and third conduit parts and adapted to supply said first part with fuel from the tank, a movable member in said valve passage adapted when in one position to close communication between said first and second passage openings, conduit means connected to the passage opening for pump adjacent its inlet, and spring means to bias said movable member to above mentioned position, to open communication between the first JAMES o. HELVERN. EvERETr L. BAUGH. 

